Apparatus and method for measuring changes in conditions in coagulating liquids

Abstract

The coagulation of blood is measured by introducing the blood into an annular gap in a beaker formed between the inner surface of the beaker and a cylindrical member depending into the beaker. The beaker is mounted on the upper end of a rod-like support. A coil arrangement about the lower part of the rod-like support impresses a circular orbiting motion on the support and beaker. Another core associated with the rod-like support measures changes in amplitude of the support produced by the development of fibrin in the blood sample in the annular gap.

I claim: 
     
       1. Method of measuring the changes of state in solidifying fluids particularly the changes occurring in the coagulation of blood, comprising the steps of mounting a measuring vessel containing an annular space on the upper end of an upright support in a measuring system, introducing a fluid into the annular space in the measuring vessel, impressing an excitation frequency on the support and providing the support with a forced oscillatory orbital movement in the resonance range of and different from the natural frequency of the measuring system, and measuring the amplitude of the support for determining the change in state of the solidifying fluid. 
     
     
       2. Method, as set forth in claim 1, including the step of selecting the excitation frequency higher than the natural frequency of the support where the fluid being measured is blood. 
     
     
       3. Method, as set forth in claim 2, wherein the natural frequency of the support is in the range of 17 and 70 Hz. 
     
     
       4. Method, as set forth in claim 2, wherein the natural frequency is 35 Hz. 
     
     
       5. Apparatus for measuring change of state in solidifying fluids, comprising an upwardly extending frame, a beaker, an oscillatory driven means for mounting said beaker, and a member inserted into said beaker, wherein the improvement comprises that said oscillatory driven means includes an upright elastic support, said beaker mounted on the upper end of said elastic support, a resilient element for supporting said elastic support, said resilient element spaced below said beaker and extending transversely of and laterally surrounding said elastic support, a coil arrangement laterally surrounding said elastic support and spaced from said beaker and resilient element for providing circular oscillatory movement to said elastic support different from the natural frequency of said elastic support so that an orbital movement of said elastic support is produced, means for measuring the oscillatory amplitude of said elastic support, and said member being rigidly supported on said frame and extending downwardly from said frame into said beaker and forming with said beaker an annular space for receiving the fluid to be measured. 
     
     
       6. Apparatus, as set forth in claim 5, wherein said elastic support comprises a vertically extending resilient rod-like member. 
     
     
       7. Apparatus, as set forth in claim 5, wherein said coil arrangement comprises a coil generating an electromagnetic alternating field. 
     
     
       8. Apparatus, as set forth in claim 7, wherein the electromagnetic alternating field of said coil arrangement revolves in the circumferential direction of said rod-like member. 
     
     
       9. Apparatus, as set forth in claim 5, wherein said means for measuring the oscillatory amplitude comprises an oscillation sensor arranged for measuring the amplitude of the orbital movement of said elastic support without contact with said elastic support. 
     
     
       10. Apparatus, as set forth in claim 9, wherein said oscillation sensor is a rigidly mounted electromagnetic coil, and a movable core attached to and extending radially from said elastic support into said coil for measuring the amplitude of said elastic support. 
     
     
       11. Apparatus, as set forth in claim 10, including an indicating instrument connected to said electromagnetic coil for providing a trace of the change in amplitude of said elastic support.